As the amount of mobile traffic increases, new frequencies are being assigned, and in the future, the large-scale deployment of TD-LTE (Time Division-Long Term Evolution) base stations in the 3.5 GHz band is expected. In TD-LTE systems, high-precision time synchronization (<±1.5 μs) between base stations is necessary in order to suppress the interference of signals between adjacent base stations. As means for achieving high-precision time synchronization between base stations, the use of global navigation satellite systems (GNSS) such as GPS (Global Positioning System) is growing. Navigation satellites in global navigation satellite systems carry high-precision atomic clocks that are synchronized to Coordinated Universal Time (UTC), and use radio waves to transmit navigation satellite signals that are synchronized thereto, so it is possible to synchronize the time to UTC by receiving these navigation satellite signals at any geographical point on earth.